Types of Stroke
- Ischemic stroke.
- Hemorrhagic stroke.
- Transient ischemic attack.
- AVM (arteriovenous malformation).
Ischemic stroke is where a blood clot blocks the flow of blood to the brain; this is the majority (87 percent) of all strokes. An ischemic stroke occurs when a blood vessel supplying blood to the brain is obstructed, thereby cutting off the supply of oxygen and nutrients. Ischemic strokes can either be embolic (due to a clot that migrated from another part of the body) or thrombotic (due to a clot that forms at the obstructed site). The underlying cause of this obstruction is the development of fatty deposits lining the vessel wall called atherosclerosis. Both types result in decreased blood flow to vital brain cells, which can lead to irreversible cell death and long-term disability.
Signs for the sudden onset of ischemic stroke include:
- Numbness or weakness in your face, arm or leg — particularly on one side of your body.
- Dizziness, loss of balance or loss of coordination; trouble walking.
- Slurred speech or trouble understanding speech.
- Difficulty seeing: Blurred vision in one or both eyes, or double vision.
Many ischemic stroke symptoms show similarities with hemorrhagic stroke symptoms.
Hemorrhagic stroke is when a blood vessel breaks, leaking blood into the brain. The blood then accumulates and compresses the surrounding brain tissue. This results in a stroke by depriving parts of the brain of blood and oxygen. It accounts for about 13 percent of stroke cases and someone suffering from it may not feel much pain.
Hemorrhagic stroke has a different set of stroke symptoms — many of which are related to increased pressure within the brain.
This type of stroke often is caused by high blood pressure, which stresses artery walls to a breaking point. The brain is highly sensitive to the presence of leaking blood. As a defense mechanism, it responds by swelling. Likewise, leaked blood can shift brain tissue against the skull. Either way, pressure builds within the skull.
There are two types of hemorrhagic stroke:
- Intracerebral hemorrhage is the most common type of hemorrhagic stroke and occurs when a diseased blood vessel within the brain bursts and allows blood to leak within the brain. This causes an increase in pressure within the brain, which causes damage to the brain cells surrounding the blood. Hypertension is the primary cause of this condition. Risk factors include alcohol and drug abuse, increased age, being male and being African American.
- Subarachnoid hemorrhage occurs when a blood vessel just outside of the brain ruptures, causing the area of the skull surrounding the brain to rapidly fill with blood. It's usually caused when an aneurysm swells, weakens the vessel and ruptures. Risk factors include middle age, family history, smoking, excessive alcohol use, being female and being African American.
Therefore, a sudden, severe "bolt out of the blue" headache or an unusual headache may result. Simultaneously, other signs of stroke include stiff neck, facial pain, pain between the eyes, vomiting or altered consciousness.
Hemorrhagic stroke symptoms include the sudden onset of:
- Weakness or inability to move a body part.
- Drowsiness, stupor, lethargy or confusion.
- Loss of sensation.
- Decreased or lost vision (may be partial).
- Speech difficulties and inability to discern familiar objects.
- Dizziness, vertigo (sensation of the world spinning around) and loss of coordination.
- Facial droop and/or difficulty swallowing.
Transient ischemic attack (TIA)
Transient ischemic attack (TIA), or a ministroke, is a brief episode of symptoms similar to those you'd have in a stroke. The cause of a transient ischemic attack is a temporary decrease in blood supply to part of your brain. Most attacks last just a few minutes.
TIA has the same cause as an ischemic stroke where a clot blocks the blood supply to part of the brain. But in contrast to a stroke, which involves a more prolonged lack of blood supply and causes some permanent damage to your brain tissue, a TIA doesn't leave lasting effects to your brain. Still, if you've had a TIA, it means there's likely a blocked or narrowed artery leading to your brain, putting you at a greater risk of a full-blown stroke that could cause more permanent damage. If you're having a TIA, get emergency medical treatment and make sure your regular physician knows about it.
Aneurysms are an abnormal widening or ballooning of a section of a blood vessel. When an aneurysm occurs in the brain, it is called a cerebral aneurysm. Aneurysms in the brain occur when there is a weakened area in the wall of a blood vessel. An aneurysm may be present from birth (congenital) or it may develop later in life (for example, after a blood vessel is injured). There are many different types of aneurysms.
AVM (arteriovenous malformation) is an abnormal connection that usually forms before birth between the arteries and veins in the brain. The cause of a cerebral AVM is unknown. and the condition occurs when arteries in the brain connect directly to nearby veins without having the normal vessels (capillaries) between them. Cerebral AVMs occur in less than 1 percent of people.
HonorHealth has three certified Primary Stroke Centers in the Valley. For more information, contact the Primary Stroke Center nearest you:
Scottsdale Osborn Medical Center
7400 E. Osborn Road
Scottsdale, AZ 85251
John C. Lincoln Medical Center
250 E. Dunlap Ave.
Phoenix, AZ 85020
Deer Valley Medical Center
19829 N. 27th Ave.
Phoenix, AZ 85027